Hi warn.jeremy,
You don't need to export your bookmarks from Edge.
See this article:
[https://support.mozilla.org/en-US/kb/import-bookmarks-internet-explorer-or-microsoft-ed Import Bookmarks from Internet Explorer or Microsoft Edge]
Instead of step 1, I use Ctrl+Shift+B to open the Bookmarks Library.

Hilfreiche Antwort

Go to Microsoft account/Edge and then to settings under "..."-- click on import/export -- click favorites -- click export to file (depends on how you are set up, but it probably will show under downloads/documents) as file name Edge and type as HTML -- click save -- go to Firefox -- click star underscored at top -- go to show all bookmarks at bottom -- click import & export in popup box-- click on import bookmarks from HTML. Done.

Go to Microsoft account/Edge and then to settings under "..."-- click on import/export -- click favorites -- click export to file (depends on how you are set up, but it probably will show under downloads/documents) as file name Edge and type as HTML -- click save -- go to Firefox -- click star underscored at top -- go to show all bookmarks at bottom -- click import & export in popup box-- click on import bookmarks from HTML. Done.